Transfer circuit system for transferring information



Aug. 25, 1964 N. H. EDSTROM TRANSFER CIRCUIT SYSTEM FOR TRANSFERRINGINFORMATION Filed Aug. 15, 1959 M M r N MN MW v5 r w m 5 & U

United States Patent ()fiice 3,146,427 Patented Aug. 25, 1964 3,146,427TRANSFER CiRCUlT SYSTEM FOR TRANSFERRHNG INFORMATION Nils HerbertEdstriim, Huger-stern, Sweden, assignor to Teiefonaktiebolaget L MEricsson, Stockholm, Sweden, a corporation of Sweden Filed Aug. 13,1959, Ser. No. 833,431 Claims priority, application Sweden Sept. 2, 19584 Claims. (Cl. 340174) The present invention refers to a transfercircuit system for transfering step-by-step information along a chainconsisting of a plurality of stages in response of stepping forwardimpulses fed to said chain.

It is known to use in counters, pulse distributors, shiftregisters andthe like, electron tubeor transistor-relaxation circuits, glow dischargetubes or bistable magnetic circuits connected in a chain in order toprovide such a step-by-step transfer of information. All such chainsinclude in their stages a network which stores energy with a certaintime constant and allows transfer of the information from one stage toanother when said stepping forward impulse occurs. A typical chain ofthis type comprises a chain of glow discharge tubes in which capacitorsare used to make certain that the tube fired at the beginning of theforward stepping is extinguished and the following tube and no othertube will be fired. It is however difficult to construct chains of saidtype comprising more than about ten elements owing to the disturbingpotentials obtained from the preceding and following stages and owing tothe fact that the time constants of the energy accumulating circuits ofthe stages of the row are normally varying within broad limits fromstage to stage. Furthermore well defined rectangular output pulses aregenerally required and such a shape is diflicult to obtain from chainsof said type. Furthermore it may be difiicult in certain cases to obtaina sufi'icient separation between two successive pulses. A furtherdrawback which in certain cases can be of importance, is that the chainin the known devices will be set to zero-condition when the currentsupply is momentarily interrupted. Certain magnetic chains comprisingmagnetic cores which have a rectangular hysteresis loop, have thefurther drawback that disturbing pulses obtained when a remagnetizingpulse is applied to a core already remagnetized, may be superposed andcause erroneous stepping.

All said drawbacks are eliminated in a chain according to the presentinvention. Said chain produces output pulses of satisfactory shape andrelatively good effect and the consumption of the chain between thestepping impulses is negligible. The chain can furthermore retain thelast occupied position for an unlimited time even if the current supplyis interrupted, and the chain will resume the same stepping sequence ithad before the interruption of current. Owing to the fact that the chaindoes not comprise any energy accumulating element having a time constantwhich can vary from stage to stage, very well defined output pulses areobtained.

A transfer circuit arrangement according to the invention forstep-by-step transmitting information along a chain consisting of aplurality of stages, in response of stepping impulses fed to the chain,comprises in each stage of the chain bistable relaxation circuits havingan input for setting said circuit to working position and another inputfor restoring the relaxation circuit to rest position and a magneticcore having a substantially rectangular hysteresis loop and providedwith three windings, a first one of said windings being connected to theoutput of said bistable relaxation circuit in such manner that it ispassed by a current magnetizing the core to a first remanence conditionwhen said relaxation circuit is in working position, a second windingbeing connected to a stepping impulse source tending to set the core toanother remanence condition, a third winding being connected to theinput for switching the relaxation circuit of the following stage insuch manner that a switching impulse is obtained as soon as the magneticcondition of the core is changed from the first to the second remanencecondition. The stepping impulse source produces in response to eachstepping two impulses separated in time, one of which impulses isapplied to said second winding on each core and the other one is appliedto the input for restoring all the relaxation circuits.

An embodiment of the invention will be explained in the following withreference to the enclosed drawing.

The chain shown in the figure comprises for sake of simplicity onlythree stages I, II and III but it can comprise a very great number ofstages. Chains having twenty stages have been tested and been found towork extremely well with safe stepping. The different stages of thechains are identical, except for a starting winding in the first stage.Each stage comprises a transistor-relaxation circuit having apnp-transistor T1 and a non-transistor T2 which are fed back in such away that either both are closed thereby defining the off ornon-conduction state of the relaxation circuit or both are conductingthereby defining the on or conduction state of the relaxation circuit(Hook-chain), and a magnetic core M1, M2 and M3 respectively having arectangular hysteresis loop. Each core is provided with three windings1-2, 3-4 and 5-6 which are arranged and connected in such a way that thewinding 1-2 causes a flux in the core having opposite direction relativeto the flux caused by the windings 3-4 and 5-6. On the core M1, there isfurthermore situated a starting winding 7-8, which is wound andconnected in such a way that it tends to magnetize the core in the samedirection as the winding 1-2. The inclined lines across the cores in thefigures indicate the magnetizing direction caused by the respectivewinding in the shown circuit, a line inclined in the right-handdirection (3-4 and 5-6) indicating that the winding will magnetize thecore to a remanence condition which in the following will be calledzero-position while a line inclined in the left-hand direction indicatesthat the core is magnetized to opposite remanence conditions, in thefollowing called one-position.

The stepping of the chain is carried out by means of an impulse sourceproducing two relatively phase-displaced impulses at two differentoutputs W1 and w2. At first a stepping impulse occurs at the input w1affecting a relaxation circuit and said stepping impulse is alwaysfollowed by a restoring impulse which restores the relaxation circuit torest position. For sake of simplicity in the figure the impulse sourcehas been indicated as two contacts K1 and K2 which are successivelyclosed for a short period of time. A contact K3 is used for connectingthe starting winding 7-8 on the core M1 to a magnetizing current source.The circuit arrangement is fed by a current source having a groundedterminal (0), a relatively positive terminal (plus) and three negativeterminals (E1, E2 and E3) where E1 is least negative and E3 is mostnegative.

Each relaxation circuit of the above mentioned type comprises a pnpand amph-transistor. The base of the pup-transistor T1 is connected throughthe base impedance r2, C1 to the collector of the npn-transistor T2,while the base of the npn-transistor T2 is connected through the baseimpedance r5, C2 to the collector of the pup-transistor T1. The emitterof the transistor T1 is grounded and the collector, in addition to beingconnected to the base of the transistor T2, is connected to impulseoutput U1 and to the terminal E1 of the potential source through theresistance r4. The base of the transistor T1 is connected through theresistance r1 to the input for restoring impulses, common for all thestages. The emitter of the transistor T2 is connected to the terminalE1, and the collector, in addition to being connected to the basecircuit of the transistor T1, is connected to ground through theresistance r3. The base of the transistor T2 is connected to theterminal E3 through the resistance rd and to the terminal E2 through thediode di and the winding 3-4 on the next preceding core of the row. Thecathode of the diode is connected to the base of T2.

While non-conducting the transistor T2 is blocked owing to the basebeing maintained at the potential E2 which is negative relatively to theemitter, by means of the conducting diode di. In the same manner thebase of the transistor T1 obtains a bias positive relatively to theemitter, through the resistance r7 so that the transistor is securelyblocked. If the base of the transistor T2 obtains a positive impulse,this transistor will become conducting and takes collector current fromground through the resistance r3: and the winding 1-2 on the respectivecore. The base potential of the transistor T1 will then decrease to sucha degree that this transistor will also become conducting. The collectorcurrent of T1 causes a potential drop along the resistance r4 increasingthe base potential of the transistor T2 to such an extent that thelatter will be maintained in a conducting state after the controllingimpulse ceases. The relaxation circuit is restored by a positive impulsebeing applied to the base of the transistor T1 which will be choked,causing that the transistor T2 will be also choked.

Transistor relaxation circuits of the type described have the advantagein comparison with other bistable relaxation circuits that the currentconsumption is negligible in rest position. The chain is consequentlybuilt in such a way that the relaxation circuits normally are in off ornon-conduction state, except upon stepping when a relaxation circuit ismade conducting. The time for which said relaxation circuit should beconducting is defined by the required duration of the-impulse occurringon the terminal U1. Said duration can be varied by varying the length ofthe period between the stepping forwardand restoring impulses as desiredwithin the whole time period between two succeeding stepping impulses.The memory function required in order to recognize th adjustment of thechain between the stepping impulses is obtained by means of the coresM1-M3.

The device functions as follows:

Let it be assumed that all the cores are from the beginning magnetizedto zero-position and that all the relaxation circuits are in thenon-conduction state. The chain is prepared for stepping by magnetizingthe core to one-position by closing a circuit momentarily from pluspotential through the winding 7-% to ground. When a stepping impulse isapplied to the series connected windings -6 in the different stages bymomentarily connecting them between plus potential and ground throughthe contact K1, only the core M1 will be remagnetized to zeroposition asthe other cores have already said position. Upon remagnetizing, apositive impulse is induced in the winding 3-4 which impulse will beapplied to the base of the transistor T2 in the relaxation circuit ofstage 11 through the diode d1 thereby rendering the transistor T2 andconsequently also the transistor T1 conducting. The transistor T 2obtains its substantial collector current through the resistance r3 andthe winding 1-2 on the core M2 for which reason the latter is magnetizedto one-position. As mentioned before, each stepping impulse on the inputW1 is followed by a restoring impulse on the input W2 which is obtainedby momentarily connecting the contact K2 to plus potential. The basepotential of the transistor T1 will be increased in such a degree thatthe transistor will be choked. Upon ceasing of the collector current,the potential of the base of the transistor T2 will decrease and thistransistor will be also choked. None of the relaxation circuits isconducting before the next stepping impulse is obtained for which reasonthe consumption in rest position is negligible. When the next steppingimpulse is obtained, the stepping process will be repeated in exactlythe same way as described hereabove, the core M2 being restored tozeroposition and the relaxation circuits of the stage III will producean impulse magnetizing core M3 to one-position. The chain shown in thefigure is intended to be used as impulse distributor for which reasonthe different stages are ring connected, that is, the winding 3-4 on thecore M3 is connected to the stepping input of the relaxation circuit ofstage I. The different, relatively displaced pulse series are obtainedfrom the outputs U1. As only one core is magnetized to one-position orzero-position respectively at the same time, the counterelectromotiveforce obtained upon remagnetizing is always the same, that is, the sumof the counter-electromotive force obtained from the remagnetized coreplus the small disturbing potentials obtained from the cores which willnot be remagnetized. Thus it is possible to have relatively long chainsdriven from the same source of stepping impulses. Experiments have shownthat it is possible with a working potential of about six volts to drivemore than twenty cores in series and to obtain a secure stepping. Ifstill longer chains are required they can be divided into a number ofgroups. In each group the windings as are connected in series and saidgroups of series-connected windings are driven parallel for decreasingthe influence of the disturbing potentials. Each group may have its ownstepping impulse source, all said driving impulse sources being ofcourse synchronized. By applying to all the cores an impulse forrestoring zero-position respectively at the same time, the countertherewill be no danger that disturbing pulses are superposed and cause anerroneous stepping which has been the case in the magnetic chainspreviously known.

The invention is of course not limited to the embodiment but it can bemodified in a number of different ways. It is, for example, notnecessary to use in the stages relaxation circuits of Hook-type but itis possible to use some other types of bistable relaxation circuits. Itis furthermore possible to let more than one impulse progress along therow with maintained relative positions, for example in certainshift-registers, in which a coded information is progressed step-by-stepfor each stepping or switching impulse on the input W1. The codedinformation can either be fed in series to a single winding 7-8, orparallel to a number of cores simultaneously in which case all the coreshave a starting winding 7-8.

A chain according to the invention can be used for very many purposes,for example as impulse counters, impulse distributors orshift-registers.

I claim:

1. In a transfer circuit system for transferring information step bystep along a multiple stage chain by means of a source of pulses forfeeding each step of said chain a stepping pulse and a reset pulse whichare separated in time, a plurality of interconnected stages, eachcomprising a bistable relaxation circuit having a first input connectionfor setting said relaxation circuit to a conduction state, a secondinput connection for setting said relaxation circuit to a non-conductionstate and an output connection, said relaxation circuit being arrangedto remain in an operative state for an indefinite period of time and tosupply current to a load during such period of time, a magnetic corehaving a substantially rectangular hysteresis loop and beingmagnetizable to a first and a second remanance state respectively andremaining in said first state and said second state respectively untilcontrolled, a first Winding on said core connected to the output of saidrelaxation circuit to magnetize the core to the first remanance state inresponse to current supplied the said output in the conduction state ofthe relaxation circuit, a second winding on said core connected to beenergized by the stepping pulse to magnetize the core by said steppingpulse to the second remanence state, a third winding on said coregenerating a pulse in response to a change caused in the remanence stateof said core and connected to the first input of the relaxation circuitnext sequential in said chain 5 to set said sequential relaxationcircuit to its conduction state, and circuit means connected to thesecond input of the relaxation circuits in said chain to feed resetpulse to the relaxation circuits in all the stages to set said circuitsto the non-conduction state.

2. A circuit arrangement according to claim 1 in which each of saidrelaxation circuits comprises a npn-transistor and a pnp-transistor, thebase of each transistor being connected to the collector of the othertransistor in the respective circuit whereby either both transistors areblocked to set the respective relaxation circuit in the nonconductionstate or both transistors are conducting to set the respectiverelaxation circuit in the conduction state.

3. A circuit arrangement according to claim 1 in which at least one ofsaid stages comprises a means for setting said one stage to a state inwhich it is sensitive to the pulses fed to said stage.

References Cited in the file of this patent UNITED STATES PATENTS2,819,395 Jones Jan. 7, 1958 2,863,138 Hemphill Dec. 2, 1958 2,876,438Jones Mar. 3, 1959 2,892,103 Scarbrough June 23, 1959 2,909,680 Moore etal Oct. 20, 1959 OTHER REFERENCES Publication I: Shift Register, by W.W. Lawrence, published in IBM Technical Disclosure Bulletin, vol. I, No.5, February 1959, p. 31.

1. IN A TRANSFER CIRCUIT SYSTEM FOR TRANSFERRING INFORMATION STEP BYSTEP ALONG A MULTIPLE STAGE CHAIN BY MEANS OF A SOURCE OF PULSES FORFEEDING EACH STEP OF SAID CHAIN A STEPPING PULSE AND A RESET PULSE WHICHARE SEPARATED IN TIME, A PLURALITY OF INTERCONNECTED STAGES, EACHCOMPRISING A BISTABLE RELAXATION CIRCUIT HAVING A FIRST INPUT CONNECTIONFOR SETTING SAID RELAXATION CIRCUIT TO A CONDUCTION STATE, A SECONDINPUT CONNECTION FOR SETTING SAID RELAXATION CIRCUIT TO A NON-CONDUCTIONSTATE AND AN OUTPUT CONNECTION, SAID RELAXATION CIRCUIT BEING ARRANGEDTO REMAIN IN AN OPERATIVE STATE FOR AN INDEFINITE PERIOD OF TIME AND TOSUPPLY CURRENT TO A LOAD DURING SUCH PERIOD OF TIME, A MAGNETIC COREHAVING A SUBSTANTIALLY RECTANGULAR HYSTERESIS LOOP AND BEINGMAGNETIZABLE TO A FIRST AND A SECOND REMANANCE STATE RESPECTIVELY ANDREMAINING IN SAID FIRST STATE AND SAID SECOND STATE RESPECTIVELY UNTILCONTROLLED, A FIRST WINDING ON SAID CORE CONNECTED TO THE OUTPUT OF SAIDRELAXATION CIRCUIT TO MAGNETIZE THE CORE TO THE FIRST REMANANCE STATE INRESPONSE TO CURRENT SUPPLIED THE SAID OUTPUT IN THE CONDUCTION STATE OFTHE RELAXATION CIRCUIT, A SECOND WINDING ON SAID CORE CONNECTED TO BEENERGIZED BY THE STEPPING PULSE TO MAGNETIZE THE CORE BY SAID STEPPINGPULSE TO THE SECOND REMANENCE STATE, A THIRD WINDING ON SAID COREGENERATING A PULSE IN RESPONSE TO A CHANGE CAUSED IN THE REMANENCE STATEOF SAID CORE AND CONNECTED TO THE FIRST INPUT OF THE RELAXATION CIRCUITNEXT SEQUENTIAL IN SAID CHAIN TO SET SAID SEQUENTIAL RELAXATION CIRCUITTO ITS CONDUCTION STATE, AND CIRCUIT MEANS CONNECTED TO THE SECOND INPUTOF THE RELAXATION CIRCUITS IN SAID CHAIN TO FEED RESET PULSE TO THERELAXATION CIRCUITS IN ALL THE STAGES TO SET SAID CIRCUITS TO THENON-CONDUCTION STATE.